Audio Power
Amplifier 60W with
TDA7294
The TDA7294 amplifier module is a monolithic integrated circuit. It is intended for use as an audio
class AB amplifier in hi-fi applications. It has a wide voltage range and output current capability,
enabling it to supply the highest power into both 4 ohm and 8n ohm loads. With the addition of a
handful of parts and a suitable power supply, this module will deliver 50W RMS into 8-ohm with 0.1%
THD. you the user must supply a heavy duty heatsink rated at 1.4°C/W. Pin 10 is the MUTE input and
pin 9 provides a STANDBY mode. Muting should always take place before standby mode is selected.
Connecting these pins permanently to the supply rail (insert links) ensures that the amplifier comes on
immediately on power up. Increasing the time constants R3-C6 and R4-C5 may eliminate any switch-
on clicks. The IC has internal thermal protection that causes the mute to cut in at 145°C and switches
the amplifier into standby at 150°C. Do not operate the module without a heatsink. The
heatsink tab on the TDA7294 IC is internally connected to the negative supply rail. If the module is
mounted inside an earthed metal enclosure then the IC must be insulated from the
heatsink. If not, the negative supply rail will be shorted to ground.
POWER SUPPLY
The maximum supply voltage of the IC is +/-40V. However the maximum dissipation of the IC would
be exceeded when using a 4-ohm load at that voltage. Therefore the supply voltage used should be
kept down to a safe +/-30V. The mains transformer used to power the module should be rated at a
minimum of 80VA. If you want to run two modules in a stereo amplifier you can use a common power
supply. In this case the transformer should be rated at 150VA.
Source: Quasar Elec.
Specifications
Input 1.3V (50W into
sensitivity 8W)
Input
10K
impedance
Frequency
15Hz - 100kHz
response
Slew rate 10V/uS
50W into 8W
(0.1% THD)
Output power
82W into 4W
(0.1% THD)
105dBa (1W /
S/N ratio
8W)
0.002% (1kHz)
THD (40W into
< 0.04% (20Hz -
8W)
20kHz)
Power Supply +/-30Vdc
Parts List for Power Amplifier
R1=180ohm C5-6=10uF 63V Electrolytic J2=3pin connector
R2-3-5=10Kohm C7=22uF 63V Electrolytic J3=2pin connector
R4=22Kohm C8=33uF 25V Electrolytic
C9-10=1000uF 63V
R6=680ohm All Resistors is 1/4W 1%
Electrolytic
C1=1.5uF 63V MKT All Electrolytic Capacitors is
IC1=TDA7294 on Heatsink
Polyester Axial
C2=2.7nF 63V MKT J1=2pin connector with
Polyester 2.54mm step
C3-4=100nF 100V MKT JP1-2=2pin Jumper with
Polyester 2.54mm step
Power Supply
Parts List for Power supply
TR1=230Vac//2X22Vac 80VA for C1=22nF 630V Polyester C8-9=10.000uF 63V For
single MKT dual Amplifier*
Amplifier
150VA for
C2....5=22nF 100V C10-11=1uF 63V Polyester
TR1=230Vac//2X22Vac dual
Polyester MKT MKT
Amplifier
C6-7=10.000uF 63V For
BR1=Diode Bridge >15A F1=Fuse 0.5A slow
single Amplifier